Vapor electric device.



W. W. CRAWFORD.

VAPOR ELECTRIC DEVICE.

APPLICATION FILED APR. 12, 1913.

1 l 5 1 345 Patented Aug. 24, 1915.

F g-I Fig.2.

v lnVenLor William W.Crawfor-ol Hi5 cffbtorney I by Wk WILLIAM W. CRAWFORD, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

VAPOR ELECTRIC DEVICE.

Specification of Letters Patent.

Patented Aug. 24, 1915.

To all whom it may concern:

Be it known that I, WILLIAM W. CRAwroun, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Vapor Electric Devices, of which the following is a spoolfication.

My invention relates to vapor electr1c devices, particularly to what is known as the high pressure vapor lamp WlllCll consists essentially of a refractory envelop, for example, a fused quartz envelop, 1 n whlch a mercury are, or other vapor arc, 1s operated at a relatively high temperature.

One of the best distinctions that may be drawn between the well known low pressure mercury arc lamp and a high pressure lamp is the following: A low pressure lamp takes about the same voltage and energy at starting as it does at normal operation while a high pressure lamp starts at a much lower voltage and takes less energy at starting than it takes under normal operating con- (litions when the lamp has come to a final the tube as in the low pressure lamp but is contracted to a comparatively narrow zone in the center of the tube. This are stream is driven about in the tube causing an undesirable flickering in the light. The use of a contraction in the quartz near the cathode which is a familiar feature of quartz lamps on the market prevents this flickering. In the vertical type of high pressure lamp, this unsteadiness of the are is considerably more pronounced than in the horizontal type, so much so that one-half the length of the are or even more, near the cathode, would be constantly moving about inside the tube. A contraction in the quartz near the cathode raises the voltage across the arc, necessitating too great a shortening of the light-giving element or else application of cooling devices, such as fins, neither of which is desirable.

I have discovered that when in the vertical type of lamp, the tube is bent near its cathode end, so that the bent portion makes an angle of somewhere about 135 with the vertical section of the tube and the sloping roof over the cathode constituted by the wall of the bent portion of the tube leaves a contracted space above the cathode, that steadiness of the arc may be secured.

My invention will be more fully understood by reference to the following description taken in connection with the accompanying drawings, in whichFigure 1 shows my improved vapor lamp in elevation; Fig. 2 is a sectional view at right angles thereto, and Fig. 3 shows a lamp when tilted for starting.

The envelop of the lamp consisting of fused quartz, or similar other refractory transparent material, comprises a vertical section 1 and an inclined section 2 at the lower end of which is a cathode chamber 3. The cathode chamber 3 is filled with a mercury body 4 to such a level that a line drawn vertically through the edge of the mercury meniscus nearest to the vertical section 1 will practically fall within or near the wall of the vertical section, the exposed active surface of the mercury thus being out of line with the are path in the vertical straight portion of the envelop. The portion of a section 2 which constitutes a sloping roof over the cathode makes an acute 7 sealed into a reentrant portion 8 of the envelop so that its end projects into that portion of the cathode chamber which assumes when the tube is tilted the lowest position as shown in Fig. 3. In that manner contact of the leading-in wire with the mercury is secured at all times when the lamp is tilted to bring the mercury into contact with the anode to initiate a flow of current through the lamp.

In a tube having the described construction of cathode' chamber, the unpleasant flickering of the arc is eliminated without changingthevoltage and current characteristics of the lamp.

A lamp of the character described is described and claimed broadly in applications, Serial Nos. 7 53,946 and 7 53,947 filed March 11, 1913', by Dr. E. Weintraub.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. A vapor electric device comprising an envelop operable in a vertical position, the lower end of said envelop being bent at an angle, a vaporizable electrode the active surface of which meets at an acute angle a wall of the inclined portion above said electrode and a coiiperating electrode in the upright portion.

2. A vapor electric device consisting of an envelop comprising a main tubular section, a cathode chamber and a connecting' curved tubular section, an anode in the vertical section, a body of mercury constituting the cathode fillin'g the cathode chamber and being when the main part of the envelop is upright, out of line with the main arc inclosing section and electrical leading-in conductors for said electrodes, said envelop being proportioned and adapted to operate with a vapor pressure at which the arc is contracted to a narrow zone in the center of the art:

space.

3. A vapor electric lamp, operating at a voltage higher than the starting voltage, comprising an envelop of refractory material proportioned to be substantially devoid of condensing space outside the are having a tubular section operable in a vertical position, a cathode container and a connecting tubular section inclined at an angle to-said vertical section, an anode near the upper closed end of the vertical section, a

body, of mercury in the cathode container,

the meniscus of said mercury being out of line withthe are pathin the tion of the envelop.

4:. A mercury vapor lamp comprising a quartz" envelop operable in a vertical positertrcalsection and being substantially devoid of consubstantially devoid of special vapor condensing means, a solid anode, and an easily vaporiz'a'bl'e cathode located at the curved end of said envelop out of line with an axis of the straight portion of the envelop passing through the anode.

6. A vapor electric lamp,-comprising a tubular envelop of refractory material devoid of special cooling means'outside the arc f path comprising a substantially straight portion and an end portion bent out of line with the longitudinal axis, an anode of refractory material and a mercury cathode ins'aid bent portion having substantially all of its exposed surface displaced out of line with the straight portion of said envelop, said exposed surface meeting the wall above at an acute angle.

It witness whereof, I have hereunto set my hand this tenth day of April, 1913. I

WILLIAM w. CRAWFORD.- Witnesses:

FRANK G. HATTIE, JOHN A. MoMANU's, Jr. 

